TrueCrypt is, or was, a long-running software project that claimed to provide strong encryption software that you could use for free on Windows, Linux and OS X. It became popular for many reasons, notably that it was free, cross-platform and apparently untainted by association with governments or commercialism. But it wasn’t truly open source, since you couldnt then do what you liked with that source code. The developers were anonymous and the development process closed: you couldn’t go to conferences and openly meet the coders.”]
Source: https://nakedsecurity.sophos.com/2014/06/20/truecrypt-mystery-forking-weirder-than-before/